48. Tina Wells

In addition to intensive millennial studying, Tina Wells curates a network of young influencers who test, share, and endorse products. "They post on Facebook, and when their friends see they have this cool job, they want to be a part of it," she says. She has also developed a tween book series called Mackenzie Blue, for which she surveyed 7-to-12-year-old girls to decide key details. They had plenty to say.